Yokogawa AFV10S-S31251 Control Unit

Configured for process control in Vnet/IP networks, the Yokogawa AFV105-S31251 (AFV105 Field Control Unit) provides direct physical/electrical execution of LFS1500 control functions for FIO node architectures.

Suffix Breakdown & Model Matrix

• AFV105: Base model for the Field Control Unit supporting Vnet/IP and FIO.
• -S: Standard type configuration.
• 3: Dual-redundant Vnet/IP, single power supply.
• 1: Standard fixed code.
• 2: 220–240 VAC power supply input.
• 1: LFS1500 control function software suite.

Hardware Specifications

Yokogawa DCS Process Control Characteristics

• Channel-to-Channel Isolation: The control station architecture maintains galvanic isolation between the internal Vnet/IP interface and the controller backplane, preventing transient noise propagation across the DCS network.
• 4-20 mA HART Loop Protocol: The unit supports transparent HART communication, enabling the mapping of secondary process variables and diagnostic data from field transmitters into the controller's control logic via the I/O node interface.
• Cold Junction Compensation (CJC): The FCU facilitates integrated CJC functionality for connected thermocouple input modules, ensuring high-accuracy temperature measurement within the process loop.
• System Integration: The dual-redundant Vnet/IP architecture ensures deterministic synchronization of process variables, maintaining control loop integrity during network communication failover events.

Frequently Asked Questions

Q: Can the internal battery backup be replaced while the FCU is in operation?

A: Yes, the battery unit is designed for hot-swapping. Ensure the system health status is verified on the engineering station prior to maintenance to prevent accidental loss of memory during the replacement interval.

Q: How does the status contact output behave during a total FCU failure?

A: The contact output consists of two terminals (NC, C) which remain in the closed position during normal operation; the contact points open upon detection of an FCU failure, signaling a fault state to external monitoring hardware.

Field Installation Guidelines

• Mounting: Install the unit into a standard 19-inch instrumentation rack. Ensure the chassis is securely fastened to the frame to provide a stable reference and electrical bond for electromagnetic shielding.
• Powering: Connect the 220–240 VAC input to a stable power source. A minimum of 48 hours of initial charging time is required for the backup battery to reach its full 72-hour protection capacity.
• Grounding: Bond the chassis ground lug directly to the central instrumentation ground bus using a low-impedance, multi-strand braided copper cable to suppress high-frequency transients.
• Connectivity: Connect the dual-redundant Vnet/IP network cables to the interface ports. Maintain physical separation between network runs to ensure fault-tolerant communication topology.